Turbine engines include a plurality of stationary vane assemblies, which are exposed to extreme thermal loads. Accordingly, provisions must be made to cool the vane assemblies. Typically, vane assemblies are cooled by routing a coolant, such as steam or compressed air, through a plurality of interior passageways formed in the vane. At least a portion of the interior cooling passages can be formed by a cooperative arrangement between a vane shroud and a shroud end cap. While such end caps have been successfully used to close and direct coolant flow in a turbine vane, the design suffers from a number of disadvantages.
For example, due to the complexity of the interfacing surfaces of the shroud and the need for internal coolant paths, shroud end caps are typically cast, such as by investment casting, and/or require extensive machining. Thus, replication in a production environment is not possible. Moreover, due to the construction of the end cap, quality inspection cannot be conducted on various brazed or welded joints between the end cap and the surrounding shroud. Further, design considerations occasionally require an increase in the height of the shrouds, which results in commensurate increases in the thickness of the end cap. Consequently, structural interferences with other components are sometimes experienced during engine installation.
Thus, one object according to aspects of the present invention is to provide a turbine vane plate assembly that can be fabricated, assembled, and inspected using conventional manufacturing methods. Another object according to aspects of the present invention is to allow replication in a production environment using conventional methods. Yet another object according to aspects of the present invention is to reduce or eliminate the use of thick solid cast and machined plates for turbine vane end caps, and preferably to use standard gauge plates. A further object according to aspects of the present invention is to permit quality inspection at each layer of assembly and fabrication. Still another object according to aspects of the invention is to provide a turbine vane assembly with a plurality of plenums and passages for directing the flow of coolant throughout the vane. An additional object according to aspects of the present invention is to provide a turbine vane assembly having engine attachment structures. These and other objects according to aspects of the present invention are addressed below.